

          commandloop [prompt] [prompt2]
               Create an interactive command loop for the current TCL
               interpreter.  This command receives commands from stdin
               and executes them.  This command is useful for non-
               interactive TCL scripts that want to enter an
               interactive mode.  Prompt is a command string to set
               the top level prompt hook to
                to, the contents of which is executed to generate the
               main prompt.  Prompt2 is a command string to set the
               down level prompt to, which is generates the prompt
               command for continuation input.  When the command
               terminates, the variables for the prompt hooks will be
               set to their old value.  If these arguments are not
               specified, the prompt hooks use their current value.
               Prompt hooks are TCL code that return as their result
               the prompt to output.  The result of the last command
               executed in the command string (which may be a return)
               will be outputted as the prompt.
